To decide who adds new blocks and what data goes into them, the network relies on a voting mechanism that requires a majority consensus.

To prevent cheating, a reputation system ensures that one bad actor can't simply run multiple nodes and sway the vote.

Most reputation systems rely on economic resources to ensure honesty.

In Ethereum, so-called “validators” must lock up 32 ETH as collateral.

The “stake” also ensures real skin in the game - dishonest or offline behavior can lead to penalties, while honest validators earn rewards for helping secure the network.

This consensus mechanism is known as Proof of Stake.